Derivative Financial Instruments - Additional Information (Details) - USD ($)	Feb. 01, 2017	Sep. 30, 2017	Sep. 18, 2017	Jun. 23, 2017	Feb. 07, 2017	Dec. 31, 2016
Derivatives
Interest rate agreement, notional amount		$ 426,124,000				$ 326,901,000
Interest Rate Swaps
Derivatives
Loss on termination of North Point Center Note interest rate swap	$ 0
Interest rate agreement, notional amount		56,124,000				56,901,000
Interest Rate Caps
Derivatives
Interest rate agreement, notional amount		$ 370,000,000	$ 50,000,000	$ 50,000,000	$ 50,000,000.0	$ 270,000,000
Interest rate cap agreement, strike price			1.50%	1.50%	1.50%
Interest rate cap agreement, premium (less than)			$ 200,000	$ 200,000	$ 200,000